Much attention is continuing to focus on the potential application of Magnetic Resonance (MR) Spectroscopy and Imaging using oxygen-17 (17O). These methods have been used in determing cerebral oxygen consumption and blood flow measurement. Successful application of 17O, however, requires a sensitive technique for detection and measurement of minute concentrations of 17O in a biological environment. Much of the difficulties lie in the small gyromagnetic ratio of this spin 5/2 nuclei, its low natural abundance, and short spin-spin relaxation-time(T2). An improvement in detection and quantification measurements of 17O can possibly be achieved using methods that indirectly measure 17O and which yield more reliable measurement of concentrations. Methods for indirect measurement of 17O have been developed whereby the underlying principle is based on the interaction of 17O with proton nuclei. It has been shown by our group that the exchange modulation of spin-spin coupling between 17O and protons (scalar coupling or J-coupling) increases proton T2-relaxation rates and causes line broadening of the proton NMR spectra. The indirect method for 17O detection that exploits the 17O decoupling effect on proton in H217O enables one to quantitate 17O via proton imaging. This method can be used in quantifying 17O in vivo . To demonstrate the feasibility of this method, we have injected a known amount of 17O in a mouse. Following the equilibrium, we have performed 17O decoupling proton spectroscopy using a double tuned coil. The percent proton signal enhancement following 17O decoupling correlated well with injected H217O concentration. Further experiments to study oxygen consumption in brain tissue are in progress.